What metaphors are used in Good Night, Mr. Tom by Michelle Magorian?

Will is riding the bus with his mother after what has been a very disappointing meeting with her. Rather than responding to Will's love, she speaks to him in the same derogatory, controlling way as before. When she puts an arm around him in order to play the part of loving mother in front of a stranger, Will feels nauseous; he "shivers at the iciness of his mother's rigid body." It is his mother's abusive character which gives him this feeling of coldness when she touches him. He knows she does not love him and can sense it in her body, even if it is not literally icy.